Core structure for electromagnets



April 10, 1951 w. A. RAY 2,548,239

CORE STRUCTURE FOR ELECTROMAGNETS NNNNN TOR, h/ILL/AMA. Q4 Y TTTTTTT YPatented Apr. 10, 1951 CORE STRUCTURE FOR ELECTROMAGNETS William A. Bay,North Hollywood, Calif., assignor to General Controls (30., Glendale,Calif., a corporation of California Application May 5, 1947, Serial No.745,951

9 Claims.

This invention relates to electromagnets, and more particularly toimprovements in core structures therefor.

An object of the invention is to providein a core structure of the typewhich comprises a cupshaped shell and a rod-like core member centrallydisposed in the shell and extending from the end wall thereof-means forsubstantially eliminating any airegap at the junction of the core memberand the shell; this object being accomplished by providing the coremember with an integral head which is so enlarged that it issubstantially ceextensive with the end wall of the shell, and whosesurface is shaped to conform exactly to the cooperating surface of theshell end-wall.

Another object is to provide simple but effective means for securing thecore-member head in intimate engagement with the shell end-wall.

Another object is to form the core member so that it constitutes abobbin for the energizing coil.

For full understanding of the invention, and further appreciation of itsfeatures and advantages, reference is to be had to the followingdetailed description and accompanying drawing, and to the appendedclaims.

In the drawing:

Figure l is a sectional view of an electromagnetically operated fluidcontrol valve embodying this invention; and

Figure 2 is a plan of the valve casing shown in Fig. l, with thearmature-closure 20 removed.

Indicated in the drawing by the numeral I I is a valve casing having aninlet I2 and an outlet I 3 separated by a partition I 4 having in itshorizontal portion three concentrically-arranged ports I5; the materialof the partition being raised around each of the ports to form valveseats I8. Communication between the inlet I2 and the chamber I 1 abovethe partition is afforded by a vertical opening I8 which leads to agenerally-semicircular trough l9 below the chamher and extending arounda major portion of the upper part of the partition to permit moreuniform distribution of fluid to the several ports. Normally resting onthe seats I6 is a disk-like closure 20.

The closure is of magnetic material so that it also serves as anarmature attractable by an electromagnet mounted on the top of the valveI casing. This electromagnet comprises a generally-cylindricalcup-shaped shell 2I, formed of magnetic sheet material, which is securedby its flanged bottom portion 22 to the raised sidewall 23 of the valvecasing; a thin diaphragm 24,

of material such as 0.005-inch-thick copper, being interposed betweenthese parts to shield the interior of the shell from the fluid in thevalve casing, as well as to serve as a non-magnetic separator for thearmature.

Centrally disposed within the shell 2| is an elongated round core-member25 having at its inner or top end an integrally-formed disk-like head 26around whose rim the material of the side wall of the shell is deformedor rolled, as indicated at 21, to secure the head in intimate engagementwith the inner surface of the end wall 28 of the shell. The top surfaceof the head 23 is preferably formed as a segment of a sphere of largeradius to ensure uniform engagement of their cooperating surfaces whenthe shell endwall is stretched over the head by the rolling operation,so that the possibility of there being an air-gap between these surfacesis substantially eliminated.

At the bottom or" the core member 25, and preferably integral therewith,is a disk-like pole piece 29 whose undersurface or pole-face is in theplane of the mouth of the shell; the diameter of the rim of the polepiece being sufficientlysmaller than the inner diameter of the shellthat a suitable working-gap for the electromagnet is formed adjacent themouth of the shell. The head 26 and pole piece 29 constitute the coremember a bobbin on which an energizing coil 30 is wound, with insulatingmaterial 3I therebetween. The leads 32 of the coil are connected toterminal posts 33 insulatingly mounted in openings through a protrudedside-portion 34 of the shell; a strap 35, of insulating material andhaving square openings cooperating with squared portions of the posts,being provided to prevent rotation of the posts when connections with anexternal circuit for the electromagnet are made or removed.

Before assembling the core member and coil in the shell, the coil leadsare soldered to the terminal posts which are then mounted in place, theleads being relatively long for this purpose. The shell is then placedin a fixture and, with the core member held firmly in position, the sidewall of the shell is rolled tightly around the rim of the core-memberhead so that the end wall of the shell is stretched into intimateengagement with the top surface of the head. If necessary, the polefaces of the shell and the core member are brought into accuratealignment by grinding.

The armature-closure 20 is normally held in sealing engagement with thevalve seats I6 by the force of a bias spring 36 compressed between thearmature and the pole piece 29. When the electromagnet is energized bypassage of current through its coil, the armature-closure is attractedinto engagement with the pole faces of the electromagnet so that thevalve ports are uncovered.

The specific embodiment of my invention herein shown and described issusceptible of modification without departing from the spirit of theinvention, and I intend therefore to be limited only by the scope of theappended claims.

I claim as my invention:

1. A core structure for an electromagnet, eom prising: a cup-shapedshell of magnetic sheet material having side walls and an end wallintegral therewith; an elongated core member centrally disposed withinsaid shell and in such spaced relation to said side walls of the shellas to define therewith a space for an energizing coil; said core memberhaving an integral enlargement at its inner end forming a relativelythin head substantially coextensive with, and shaped to conform to, theinner surface of said end wall of the shell; and means for securing Isaid head in intimate engagement with said surface.

2. A core structure as defined in claim 1, and wherein said means forsecuring said head to said end wall of the shell comprises a reentrantportion of the side wall of the shell in engagement with the rim of thehead.

3. A core structure as defined in claim 1, and wherein the conformingsurfaces of said head and of said end wall of the shell are respectivelyconvex and concave.

4. A core structure for an electromagnet, comprising: agenerally-cylindrical cup-shaped shell of magnetic sheet material havinga side wall and an end wall integral therewith; an elongated round coremember centrally disposed within said shell and of such diameter as todefine with said side wall of the shell a relatively-large annular spacefor an energizing coil; said core member having an integral enlargementat its inner end forming a disk-like head whose diameter issubstantially equal to the inner diameter of the shell, the outersurface of said head being shaped to conform to the inner surface ofsaid end wall of the shell; and means for securing said head in intimateengagement with said end wall.

5. A core structure as defined in claim 4, and

wherein said means for securing said head to said end wall of the shellcomprises a reentrant portion of the side wall of the shell inengagement with the rim of the head. 7

6. A core structure as defined in claim 4, and wherein said outersurface of said head forms a segment of a sphere of large radius.

7. A core structure for an electromagnet, comprising: agenerally-cylindrical cup-shaped shell of magnetic sheet material havinga side wall and an end wall integral therewith; an elongated round coremember centrally disposed within said shell and of such diameter as todefine with said side wall of the shell a relatively-large annular spacefor an energizing coil; said core member having an integral enlargementat its inner end forming a disk-like head whose diameter issubstantially equal to the inner diameter of the shell, the outersurface of said head being shaped to conform to the inner surface ofsaid end wall of the shell; and means for securing said head in intimateengagement with said end wall; the other end of said core member beingenlarged to provide a disk-like pole piece whose face is in the plane ofthe mouth of the shell, said head and said pole piece constituting thecore member a bobbin for said coil.

8. A core structure as defined in claim 7, and wherein said means forsecuring said head to said end wall of the shell comprises a reentrantportion of the side wall of the shell in engagement with the rim of thehead.

9. A core structure as defined in claim 7, and wherein said outersurface of said head forms a segment of a sphere of large radius.

WILLIAM A. RAY.

EEFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,654,642 Geissinger Jan. 3, 19281,965,053 Powers July 3, 1934 2,155,358 Cyr Apr. 18, 1939 2,353,835 Laneet al. July 18, 1944 2,411,778 De Wilde Nov. 26, 1946 2,422,260 Ray June17, 1947 2,465,036 Ray Mar. 22, 1949 2,479,398 Parsons Aug. 16, 1949

